For instance, the Advanced Host Controller Interface (AHCI) standard applied to, for example, PCIe-SSD is provided for a host bus adaptor (HBA) based on the Serial Advanced Technology Attachment (SATA) protocol. According to AHCI, since the HBA performs serial processing of processing commands one by one, it is inhibited from accepting other commands while a data transfer corresponding to a predetermined command is being performed between the HBA and a device.
Accordingly, even where a plurality of commands are sequentially queued from a host to the HBA independently of data transfer therebetween, as in, for example, Native command Queuing (NCQ), the data transfer between the HBA and the device is performed only using a slot that is activated by, for example, a tag (command) included in a protocol called DMA setup FIS.